When you look at the periodic table, it is very apparent that the elements have been organized into some kind of order, in rows and columns. The first and most important division within the table is the individual columns, known as Groups or Families. Just as most groups or families tend have some specific characteristics or traits in common (like being tall or having brown eyes), the elements have certain properties that are defined by the group they are in.
The groups are numbered according to several different conventions, but the most commonly accepted method is the IUPAC (International Union of Pure and Applied Chemistry) system, which labels the groups from left to right with numbers 1 through 18. This is the system we will be using here.
Let's take a tour of the different groups one at a time. The first group we'll examine is the Alkali Metals.